Teletypewriter



Patented July 29, 1941 TELETYPEWRITER Charles R. Doty, Yonkers, N. Y., assignor to International Business Machines Corporation,A New York, N. Y., a corporation of New York Application November 9, 1939, Serial No. 303,526

1 Claim.

This invention relates to typewriters and, more particularly, to typewriters adaptable for use as translating units in remotely controlled printing telegraph systems and the like. l

It is the general object of the present invention to provide a simplified and improved permutation bar system associated with the character keyboard of a typewriter and adapted to operate the key levers in accordance with permutation or combinational signals received.

More specically, it is the object of the invention to provide a mechanical permutation bar system of unique construction and with an improved electrical readout for special uses such, for example, as operating the key levers of a typewriter. I

Other objects of the invention will be pointed out in the following description and claim and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a cross sectional view of one type of power operated typewriter and the associated` permutation bar unit.

Fig. 2 is a sectional view showing the controlling clutch and magnets of the permutation bar unit.

Fig. 3 is an exploded view of the permutation bar clutch unit.

Fig. 4 is a detail view of the drive gears for the bars.

Fig. 5 is a schematic diagram of the simple operating circuits of the machine.

Figures 6 to 6B are detail views of the clutch unit.

For illustrative purposes, this invention is shown as embodying a Well known form of recording unit, which may be the Electromatic typewriter shown in Patent No. 1,777,055, and hencerequires only the following brief description.

Referring to the drawings and particularly to Fig, 1, in the embodiment illustrated in the drawing well known means are provided for actuating the type bars (not shown) by power operated devices comprising a power driven roller I0.

A cam I I is pivoted on one arm of a ,bell crank lever I2 pivoted in the frame, the other arm of which is operatively connected with one arm of bars (not shown) in a well known manner. VThe lever I2 is actuated by the cam II when the latter engages the driven roller I0 to be operated thereby. The engagement of the cam II with the power roller is controlled by means of the key lever I1 in a manner which will now be described.

Thev cam II is resiliently engaged by a springpressed arm which tends to turn it into engagement with the power driven roller or a stop 2| on a lever 22 pivoted on the bell crank I2 and normally arranged in the path of a lug on the cam, When the lever 22 swings to move its stop out of the path of the lug, the arm 20 swings the cam into engagement with the power roller to be actuated thereby to swing the bell crank I2 to actuate its connected mechanism.

The lever 22 has an arm 24 which is provided with an offset projection 25 at its end which y projects laterally through an opening in the bell crank I2 and engages the bifurcated llower end vided in the form of individual solenoids 30 which have their armatures 3I connected by a link 32 to the respective key levers I'I in such a manner that upon energization of the solenoids, the key levers are operated. a

The permutation bar `mechanism associated with the key levers for controlling the energization of the key lever solenoids is shown in the drawings to comprise generally a plurality of slotted shafts or bars having an elongated, cam shaped cross section, the slots 36 of which are cut in the upper portions of the bars as best illustrated in Fig. 3. The bars are normally maintained inoperative so that seeker levers 31, one for each key lever, are locked in an inoperative position by engagement with the high portions of certain of the bars. Gear units 4I (Fig. 4) are provided at each end of the permutation bar device, comprising three sets of gears, one for each shaft or bar 35. The gears 38, 39, and 40 are rotated continuously by drive gears 42 and are connected to the associated bars 35 by individual clutches 43 (Fig. 3) to drive said bars one revolution. The clutches 43 are controlled*` by magnets 44 which are energized by control signals and in combinations in accordance with shown, are supported in the end plates 43 (see l Fig. 2) attached to the gear vunits 4I which are secured to the supporting casting indicated generally at 43. The seeker levers 3.1 are positioned over the permutation bars 35 and are pivotally supported at the ends thereof by rod 43 suitably carried by members 43 mounted on the adjacent casting 43. Individual springs 33 are attached to the levers 31 to urge the levers against the permutation bars 33. The levers 31 at their other ends are arranged to operate individual sets of contacts 31a., Thus, it will be seen that upon depression of a seeker lever 31 by spring 33, the related contacts 31a will be moved to a closed position by virtue of a camming action exerted by the seeker lever in its downward movement. The levers 31 are kept in correct alignment by means of the comb member 54 attached to the said supporting casting. Closure of any of the sets of. contacts 31a brings about the energizationrof one of the key lever solenoids 33 -as is obvious from Fig. 5. Each of the solenoids 33 upon becoming energized attracts its armature 3| which is connected through link 32 to a key lever I1, thereby causing lever I1 and its associated type bar to be operated.

The permutation bars are slotted in accordance. with any desired permutation code, the slots as shownbeing arranged so that upon rotation of certain of the bars, one seeker lever 31 is selected and permitted momentarily to be depressed into the slots by spring 53 thereby actuating the -associated contacts 31a and key lever I1.

The bars are connected for rotation by the power driven roller I3 of the typewriter by reason of a connecting belt 53 which rotates shaft 55. Attached to shaft 55 is a pair ofA driving gears 42, the gears positioned so as to engage the gears 33 (Fig. 4) in each gear unit 4I. The gears 33 are adapted to rotate the gears 33 and 43. Thev gears 33, 33, and 40 are attached to individual stub shafts 56 (Fig. 3) upon which are mounted ratchet Sears 51. Associated with each ratchet gear 51 is a clutch unit 43 which is secured to the permutation bar 315. A clutch unit is provided for each bar. The principles of operation of the sets of clutch units and gear units are identical and consequently only one set need be explained. It will be seen from Fig. 4 that the directions of motions of the clutch gears 33,

the clutches 43 are made right-hand and lefthand to correspond thereto.

A controlling magnet 44 is provided for each clutch 43. Referring to Figs. 3 and 5, the mag- 33 is iixed in the said member 33 land acts as a guide for spring 33. The dog 33 is shaped so as to nt over the said spring and spring post and when mounted in the channel provided in the housing member 33 it is seen that the spring 33 tends to urge or maintain the'dog 33 to the right as viewed in Fig. 6A. The dog 33 and housing member 33 are recessed so as to receive the dog lift lever 32 which when inserted in the housing member is adapted to be rotated slightly or pivoted about onel end thereof. The other end of the dog lift lever extends beyond the housing member'and is arranged to engage the stop arm 3I whenever magnet 44 is deenergized. Movement ofthe dog lift lever 32 moves the recessed dog 33 and when blocked by the sto arm 3I as shown in Fig. 3 positions the dog 3 to the extreme left-hand position against the action of spring 33. A spring-pressed stop 31 engages a notch 33 provided in the housing member 35. the bar 33 to be rotated in a counterclockwise direction as viewed in the figure, thereby also locking the clutch unit 43 so long as the magnet 44 remains deenergized.

Upon energization of the magnet, its larmature 33 is attracted and positions the stop arm downwardly about the pivot 33 and out oi. en-l gagement and the path of dog lift lever 32. The spring 33 then forces the dog 33 to the right as viewed in Fig. 5 into engagement with the constantly rotating ratchet gear 51.

The signal condition impressed upon the magnet 44 lasts momentarily, so that the stop 3| is 4(i0 33, and 43 are different, and because of this fact positioned in the path of the dog lift lever 32 before one revolution of the clutch has been completed. As the clutch is rotated by the gear 51 and completes its revolution the dog lift lever engages the stop 3l, and as the clutch continues its rotation with the lift lever 32 held stationary by the stop 3|, the said lift lever is rotated about its end positioned in the housing member 35 to slide the toothed dog 33 out of engagement with the ratchet gear 51. vWhen the tooth 34 is brought out of engagement with the said ratchet,

driving power is removed from the clutch and permutation bar. 33 normally would have a tendency to rotate the permutation bar in a reverse direction and permit the tooth 34 to again engage the ratchet gear; however, as previously explained the clutch and bar 35 are locked in the inoperative position by means of the stop 31. Due to the relative high speed of operation, when the toothed dog is forced out of engagement with the ratchet by means of the stop 3|, the momentum of the rotating permutation bar and clutch is sufficient to rotate the bar and clutch slightly beyond the position where the tooth 34 just becomes disengaged from the ratchet gear; this carry-over is sufficient to permit the spring-pressed stop 31 to engage the notch 33 locking the clutch and bar against reversed rotation and insuring suicient clearance between the dog tooth and the ratchet so as to prevent chattering.

The remaining permutation bars are rotated in a like manner upon energization of the associated clutch magnets 44. The magnets are energized practically simultaneously so that when a particular combination of signals causes certain of the magnets to be energized, the corresponding permutation bars are permitted to be rotated one revolution, permitting oneseeker lever 31 to` drop in the aligned 'slots on the permutation bars which have remained stationary, thereby The spring 33 within the dog actuating a set of contacts 31a to cause recording of a character on the power operated typewriter accordingly in the manner described previously herein.

'I'he design of the bars'and seeker levers of the permutation bar unit is such that a long duration of closure of any of the contacts selected for operation is assured. Downwardly extending tab portions are provided on the levers 31 and these portions facilitate the cooperation of the levers with certain of the slots 36 of. bars 35 as previously described. The elongated cross section of the bars supplies a longldwell which permits the selected seeker lever to remain in its operated position for the greater part of a revolution of the rotated bars. The selected seeker lever thus holds the contacts 31a closed for the period in which the long dwells of the rotating bars are moving by the lever, which period is suiiiciently great to adequately energize the proper key lever solenoid 30. The-bars may be made round instead of oblong in cross-section but if this is done, the speed of operation would necessarily befpmore limited because of a shorter duration of closure of the contacts 31a during each revolution of the bars. The slots 36 are cut in the top of all the bars and, with the clutches latched up, these slots stand ready to receive their related seeker levers immediately upongrotation of predetermined combinations of bars 35 in it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without 4 departing from the spirit of the invention. It is tlieintention, therefore, to` be limited only as indicated by the scope of the following claim.

accordance with the preselected permutation code. At the end oi. one revolution, the bars are restored to their normal position. Thus it is seen that upon reception of a signal the bars 4 are rotated, but even in this event all the seeker levers are maintained in a locked position except the selected one, in this manner making it impossible to depress more than one -seeker lever Y What is claimed is:

A character translating device of the class described comprising, in combination, a keyboard having a plurality of key levers one for each character, individual electromagnets for operating said key levers, a plurality of rotatable permutation elements each having an4 elongated cross-section in the shape of a cam `with a single from said slots by the high portions of the periphf I eries ofothers of said elements, means to rotate predetermined combinations of the permutation elements in accordance with the characters to be translated to select said seeker levers for operation by removing the high portions of the rotated elements from the paths of predetermined ones of the seeker levers to cause the selected levers to seek the slots in the elements remaining stationary with which the latter levers are aligned,

V and individual circuits for energizing the magmined period during which time the long dwells nets to operate the related character key levers including circuit-closing means rendered effective by the operated seeker levers for the predeterof the rotatedpermutation elements are moving by said selected seeker levers, said period being tion of the magnets in the circuits rendered f eiective by said seeker levers.

CHARLES R. DOTY.

of suilicient duration to insure positive energiza- 

